A Continuous 2π Phase Shifter for Ka-Band Applications

A Ka-band continuous phase shifter is presented in this paper. A grounded co-planar wave (GCPW) transmission line loaded with a high dielectric ceramic slab is employed to achieve continuous phase shift over the operating frequency band (28-31 GHz) for high performance phased-array applications. A piezoelectric transducer (PET) is used to precisely control the gap between the slab and the GCPW; hence, the phase state of the phase shifter is controlled. More than 2 pi phase shift can be achieved by the proposed phase shifter, which is implemented in 3x3mm(2) area size by employing a meander shaped GCPW line. Extensive measurements have been performed showing a high figure of merit (FOM) 180 degrees/dB at 28 GHz with high repeatability at room temperature.